The present invention relates to clutch plates in general, and more particularly to improvements in clutch plates which can be used with advantage in friction clutches of automotive vehicles. Still more particularly, the invention relates to improvements in clutch plates of the type wherein the hub comprises two coaxial sections and wherein the inner section has an annulus of axially parallel external teeth mating, with at least some angular play, with the internal teeth of the outer section.
It is already known to provide a clutch plate with a composite hub whose sections are turnable within limits relative to each other as a result of a certain amount of play between the internal teeth of the outer section and the external teeth of the inner section. The two sections are held against axial movement relative to each other and a friction generating device is interposed between the two sections to yieldably oppose the angular movement of the outer section relative to the inner section and/or vice versa. Reference may be had, for example, to commonly owned U.S. Pat. No. 3,556,273 granted Jan. 19, 1971 to Paul Maucher for "Clutch disc with vibration dampers in series". The friction generating means between the inner and outer sections of the clutch plate which is disclosed in this patent comprises tubular bearing-like resilient elements which oppose rotation of the sections relative to one another. A ring-shaped spring is provided to hold the two sections against axial movement relative to each other. The magnitude of the resistance which the tubular resilient elements offer to relative rotation of the two sections about their common axis depends on the nature of the material of such resilient elements, and the resistance which the resilient elements offer to rotation of the one section relative to the other section and/or vice versa is likely to change with time. This can adversely influence the transmission of torque between the part or parts which drive the patented clutch plate and the part or parts which are driven by such clutch plate.